Diagnosis of acute appendicitis by modified Alvarado score vs. ultrasound based on histopathological findings: A comparative study

Abstract

Background: Acute appendicitis commonly causes emergency surgery. Clinical examination accuracy ranges from 71-97%; despite ultrasound diagnostic improvements, accuracy depends mainly on operator experience. This study uses a modified version of the Alvarado score, excluding one laboratory finding (shift to the left of neutrophil maturation). As differential count is not routinely undertaken in the study site (Erbil), patients were scored out of 9 rather than 10 points. This study compares the diagnostic accuracy of ultrasound and modified Alvarado score in the diagnosis of acute appendicitis, to reduce appendicitis mortality and morbidity, and reduce rates of negative appendicitis.

Methodology: The study design was a prospective cross-sectional comparative study, which took place in the Surgery, Radiology and Histopathology Department of Rizgary Teaching Hospital and Rozhalat Emergency Hospital, Erbil, from January 2019 to December 2021. All patients who presented to the emergency room with signs and symptoms of acute appendicitis were clinically evaluated. Patients who had a modified Alvarado score > 8 were considered positive for modified Alvarado, and those scoring 6-7 were considered negative for modified Alvarado and were considered for ultrasound examination; among the latter, those with positive ultrasound results were included in the study.

Results: Among the 468 patients, 257 (54.9%) were male and 211 (45.1%) were female (1.22:1 male: female ratio), with a mean age of 23.45 ± 2.1 years (ranging from 12 to 56 years). Modified ultrasonography has a sensitivity of 82% and an accuracy of 79.9%; the modified Alvarado score had a sensitivity of 95.2% and an accuracy of 87%. There was no association between the mean age of male and female patients with the histopathological results. The most commonly affected age group was the cohort 21-30 years (51.7% of all patients). The number of patients with positive histopathology was 411; negative histopathology was recorded for 57 patients, with no association between histopathological results and gender. There was a significant association between symptoms (cough signs, localized tenderness signs, and pointing signs) and positive histopathology findings.

Conclusion: Modified Alvarado score has higher sensitivity than ultrasound, while ultrasound has a higher specificity. Neither tool is superior to the other, nor both need to be used together to reduce negative appendectomy rates.